Search results for "HOMEOSTASIS"

PPAR in Cardiovascular Disorders

2016

Peroxisome proliferation-activated receptors (PPARs) are ligand-inducible transcription factors that, upon binding their ligands, translocate into the nucleus, where they regulate transcription of numerous genes that have the peroxisome proliferator response element (PPRE) in the promoter region [1]. In humans, there are 3 PPAR isoforms: PPAR-α, PPAR-β/δ, and PPAR-γ. The isoforms have partially overlapping spectra of activity and are differently expressed in organs and tissues [2]. PPAR-α is expressed mostly in tissues characterized by high catabolic activity, including skeletal muscle, liver, proximal tubular cells in kidneys, and brown fat. This PPAR isoform regulates components of β-oxid…

Chatting Between the Brain and White Adipose Tissues

2012

Over the past decades, numerous papers have been published demonstrating the importance of the relationships between the brain and white adipose tissues in regard to body weight and metabolism regulation. Indeed the brain mainly via the sympathetic nervous system control body fat mass both by regulating adipocytes metabolism (lipolysis and lipogenesis), secretory activity (leptin and other adipokines) as well as development. In turn fat mass will send information to some brain areas via sensory nerves as well as via changes in metabolic and hormonal signals. Altogether these data are in support of a feedback loop between white adipose tissues and the brain. This crosstalk plays a major role…

Adaptation of neuronal cells to chronic oxidative stress is associated with altered cholesterol and sphingolipid homeostasis and lysosomal function

2009

Chronic oxidative stress has been causally linked to several neurodegenerative disorders. As sensitivity for oxidative stress greatly differs between brain regions and neuronal cell types, specific cellular mechanisms of adaptation to chronic oxidative stress should exist. Our objective was to identify molecular mechanisms of adaptation of neuronal cells after applying chronic sublethal oxidative stress. We demonstrate that cells resistant to oxidative stress exhibit altered cholesterol and sphingomyelin metabolisms. Stress-resistant cells showed reduced levels of molecules involved in cholesterol trafficking and intracellular accumulation of cholesterol, cholesterol precursors, and metabol…

The Homeostasis of Brain Choline

1993

The interest in the homeostasis of brain choline is reinforced by the role of choline as immediate precursor of acetylcholine, phosphatidylcholine and other phospholipids in the brain. In order to obtain a comprehensive view of the mochanisms of homeostasis it appeared necessary to elucidate the negative arteriovenous difference of choline across the brain (net release), a phenomenon that has been known for 20 years and is present in mammals and in man. This finding prompted an intense search for a de novo synthesis of choline in the brain. We detected in anaesthetized rats a reversal of the net release into a net uptake (positive arterio-venous difference), when the plasma level of choline…

Glucose Metabolism in Children With Growth Hormone Deficiency

2018

Background: The growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis has a fundamental impact on glucose metabolism. Therefore, both untreated GH deficiency (GHD) and GH treatment (GHT) may be associated with some metabolic alterations, although the abnormalities of glucose metabolism have been investigated by relatively few studies as main outcomes. Aim: The present review summarizes the available data on glucose metabolism in children with GHD, providing an overview of the current state of the art in order better to clarify the real metabolic impact of GHD and GHT. Methods: Among all the existing studies, we evaluated all original studies that fulfilled our criteria for analysis …

Reduced incidence of type 2 diabetes in patients with chronic hepatitis C virus infection cleared by direct-acting antiviral therapy: A prospective s…

2020

Aim HCV infection increases the risk of type 2 diabetes mellitus (T2DM). However, it remains still unclear whether HCV clearance by direct-acting antivirals (DAA) reduces T2DM. Therefore, the effect of HCV eradication on T2DM incidence was assessed. Methods A prospective multicenter case-control study was performed, which included 2,426 HCV patients, 42% of which with liver fibrosis F0-F2 and 58% F3-F4. Study population consisted of a control group including 1099 untreated patients and 1327 cases treated with DAA. T2DM incidence was assessed during a follow-up median period of 30 [IQR: 28-42] months. Risk factors of T2DM were assessed by Cox regression model (Relative risk (RR), Hazard risk…

Glutathione-dependent resistance of the European eel Anguilla anguilla to the herbicide molinate

2001

Eels of species Anguilla anguilla were exposed to 5/4 LC50 (41.8 mg/l) of the herbicide molinate for 96 h in a time to death (TTD) test. Glutathione content (GSx, GSH, GSSG), glutathione reductase (GR) and gamma-glutamyl transpeptidase (gamma-GT) activities were determined in the liver and muscle tissues of dead and surviving (intoxicated) animals and compared to control values (non-exposed eels). TTD was positively correlated to hepatic GSH, GSH:GSSG ratio, hepatic and muscular GR, but negatively correlated to muscular GSH, which was severely depleted. Furthermore, glutathione and enzyme activities were intercorrelated, especially GSH and GR. These results indicate that eels which were abl…

Diabetes Secondary to Acromegaly: Physiopathology, Clinical Features and Effects of Treatment.

2018

Acromegaly is a rare disease due to chronic GH excess and to the consequent increase in IGF-1 levels. Both GH and IGF-1 play a role in intermediate metabolism affecting glucose homeostasis. Indeed, chronic GH excess impairs insulin sensitivity, increases gluconeogenesis, reduces the glucose uptake in adipose tissue and muscle and alters pancreatic β cells function. As a consequence, glucose metabolism alterations are a very frequent complication in acromegaly patients, further contributing to the increased cardiovascular risk and mortality. Treatment modalities of acromegaly differently impact on glucose tolerance. Successful surgical treatment of acromegaly ameliorates glucose metabolism a…

Dexamethasone prevents hearing loss by restoring glucocorticoid receptor expression in the guinea pig cochlea

2015

Objectives/Hypothesis Dexamethasone is widely used in the treatment of various inner ear diseases. However, knowledge about its direct impact on glucocorticoid receptor (GR) expression is still limited. Study Design Prospective animal study in male guinea pigs. Methods A therapeutic concentration of dexamethasone (8mg/mL) or a physiological concentration of NaCl (0.9% solution) were intratympanically injected into the ears of guinea pigs (n = 10 in each case) 14 hours prior to 90 dB noise exposure (1 hour). Eighteen ears were exposed to noise only. Seven untreated ears were used as controls. Auditory brainstem responses were recorded prior to noise exposure or treatment and 2 hours thereaft…

2015

Cells secrete extracellular vesicles (EVs) by default and in response to diverse stimuli for the purpose of cell communication and tissue homeostasis. EVs are present in all body fluids including peripheral blood, and their appearance correlates with specific physiological and pathological conditions. Here, we show that physical activity is associated with the release of nano-sized EVs into the circulation. Healthy individuals were subjected to an incremental exercise protocol of cycling or running until exhaustion, and EVs were isolated from blood plasma samples taken before, immediately after and 90 min after exercise. Small EVs with the size of 100–130 nm, that carried proteins character…